The following discussion is provided solely to assist the understanding of the reader, and does not constitute an admission that any of the information discussed or references cited constitute prior art to the present invention.
Ethyl acetate can be produced from acetaldehyde according to the Tischenko reaction:2CH3CHO←→CH3COOC2H5 
When acetaldehyde is produced from ethanol, ethyl acetate can be produced from ethanol according to the following reaction:2C2H5OH←→CH3COOC2H5+2H2 
Alternately, ethanol can react with acetaldehyde according to the following reaction:C2H5OH+CH3CHO←→CH3COOC2H5+H2 
Conversion of primary alcohols into esters and ketones using copper catalyst is described by K. Takeshita in the Bulletin of the Chemical Society of Japan, (1978) vol. 51(9), pp 2622-2627.
U.S. Pat. No. 4,996,007 describes a process for the oxidation of primary alcohols to aldehydes, esters and acids. A primary alcohol is reacted with oxygen, with a catalyst selected from ruthenium, rhodium, platinum, palladium, rhenium and mixtures thereof, with the option of quaternary C1 to C20 alkyl ammonium co-catalyst, and dihydrodihydroxynaphthalene, dihydroxyanthracene or a mixture thereof as an oxygen activator.
In U.S. Pat. No. 4,220,803 catalytic dehydrogenation of ethanol for the production of acetaldehyde and acetic acid using a supported copper oxide essentially free of barium is proposed.
U.S. Pat. No. 4,052,424 suggested a silver-cadmium alloy catalyst for use in production of alkyl alkanoate esters, by contacting a primary alkanol in the vapor phase with the catalyst at a temperature of between about 250° C. and 600° C.
In U.S. Pat. No. 4,440,946 there is described a process for producing a carboxylate ester which comprises contacting a mixture of alcohol and aldehyde in the vapor phase with a co-precipitate composition comprising silver-cadmium-zinc-zirconium which is substantially in the free metal form.
Use of the Tischenko reaction for the production of mixed esters from aldehydes is described in U.S. Pat. No. 3,714,236.
U.S. Pat. No. 5,334,751 describes production of ethyl acetate by reaction of ethanol and oxygen in the presence of a solid catalyst that contains crystalline TiP2O7 and has the formula PdaMbTiPcOx, where M is Cd, Au, Zn, Tl, or an alkali metal or alkaline earth metal, a is 0.0005-0.2, b is 0.3a, c is 0.5-2.5, x has a value to satisfy the valencies, and Ti and P of the crystalline TiP2O7 represent part of the crystalline TiP2O7.
BR-A-91/04652 describes pre-treatment of a palladium on a silica carrier catalyst for production of ethyl acetate by direct oxidation of ethanol with air.
Production of esters from primary alcohols by dehydrogenation using bromous acid or a salt thereof in acid medium is described in JP-A-59/025334.
In SU-A-362814 there is described a process for production of ethyl acetate by dehydrogenation of ethanol at 180° C. to 300° C. in the presence of a copper catalyst containing zinc as an activator with an ethanol feed rate of 250 to 700 liters per liter of catalyst per hour.
The dehydrogenation of ethanol to form ethyl acetate is described in GB-A-287846. This proposes use of a dehydrogenating agent, such as a copper catalyst, a temperature of from 250° C. to 500° C., and a pressure of more than 10 atmospheres (1.013×106 Pa).
Vapor phase contact of ethanol at a temperature above its critical temperature with a catalyst comprising copper and a difficultly reducible oxide, such as zinc oxide or manganese oxide, is proposed in GB-A-312345, use of a temperature of 375° C. and a pressure of 4000 psi (27.58 Mpa) being suggested.
GB-A-470773 teaches a process for conversion of ethanol to ethyl acetate by dehydrogenating ethanol over a catalyst consisting of a reduced metal, for example, copper on infusorial earth with 10% uranium oxide as promoter, maintained at a temperature of 220° C. to 260° C., removing by condensation some of the gas-vapor product rich in hydrogen resulting from the reaction, and returning the gaseous remainder rich in hydrogen to the catalyzing zone.
EP-A-0151886 describes a process for the preparation of C2+ esters of alkyl carboxylic acids from C2+ primary alcohols which comprises contacting a vaporous mixture containing a primary C2+ alkanol and hydrogen in an alkanol:hydrogen molar ratio of from 1:10 to about 1000:1 at a combined partial pressure of alkanol and hydrogen of from about 0.1 bar (103 Pa) up to about 40 bar (4×106 Pa) and at a temperature in the range of from about 180° C. to about 300° C. in a catalytic reaction zone with a catalyst consisting essentially of a reduced mixture of copper oxide and zinc oxide, and recovering a reaction product mixture containing a primary C2+ alkyl ester of an alkyl carboxylic acid which ester contains twice as many carbon atoms as the primary C2+ alkanol.
In EP-A-0201105 there is described a method for converting primary alcohols, such as ethanol, to their corresponding alkanoate esters which involves the regulation of the mole feed ratio of hydrogen gas to alkanol in the reaction zone of a copper-chromite containing catalyst.
One method of separating ethyl acetate from ethanol and water involves extractive distillation with an extractive agent comprising polyethylene glycol and dipropylene glycol, diethylene glycol, or triethylene glycol as described in U.S. Pat. No. 4,569,726 or with an extractive agent containing dimethyl sulphoxide as described in U.S. Pat. No. 4,379,028.
Separation of ethyl acetate from a composition comprising ethyl acetate, ethanol and water is described in JP-A-05/186392 by feeding the composition to a distillation column to obtain a quasi-azeotropic mixture comprising ethyl acetate, ethanol and water, condensing it, separating the condensate into an organic layer and an aqueous layer, returning the organic layer to the column, and recovering ethyl acetate as a bottom product from the column.
EP-A-0331021 describes how carbonylation of olefins to produce monocarboxylate esters causes formation of aldehydes and acetals as byproducts. Monocarboxylate esters produced in this way are subjected to a three step purification process involving treatment with a strongly acidic agent, followed by hydrogenation and distillation. The initial treatment with a strongly acidic agent is intended to convert acetals to vinyl ethers and aldehydes and acetals to aldols. The subsequent hydrogenation step then converts these compounds to byproducts which are more easily separated from the desired monocarboxylate ester.
EP-A-0101910 contains a similar disclosure regarding carbonylation of olefins to give monocarboxylate esters. It proposes treatment of the monocarboxylate ester with hydrogen at elevated temperature in the presence of an acidic ion exchanger or zeolite doped with one or more metals of Group VIII of the Periodic Table, followed by hydrogenation. It is stated that acetals present as byproducts are converted to vinyl ethers which are converted by hydrogenation to low boiling esters or the aldehydes and acetals are converted to high boilers by an aldol reaction. Unsaturated ketones are converted to saturated ketones.
U.S. Pat. No. 4,435,595 describes the use of reactive distillation to produce high-purity methyl acetate, by esterifying methanol and acetic acid. The process provides for the use of acetic acid and methanol which flow in counter-current through a single reactive distillation column in the presence of an acid catalyst. The acetic acid, in addition to being a reagent, also acts as an extracting agent for the non-reacted methanol and for the water which has been produced. Therefore, the methyl acetate is separated continuously from the acetic acid and removed from the top of the column.